Q o o o o c



(No Model.) 2Sheets--'Sheet 2. r

R. W. MEWES.-

STEAM GENERATOR.

' No. 576,674. Patented Feb.9,1897.

UNITED- STATES PATENT ()FFICE.

RICHARD VATSON MElVES, OF BLACKHILL, ENGLAND.

STEAM-G EN ERATO R.

SPECIFICATION forming part of Letters Patent No. 576,874, dated February9, 1897. Application filed October 15,1396. Serial No. 608,949. (Nomodel.) Patented in England August 14, 1894, No. 15,490.

To all whom it may concern:

Be it known that I, RICHARD WATSON MEWES, a subject of the Queen ofGreat Britain, residing at Blackhill, in the county of Durham, England,have invented new and useful Improvements in Steam-Generators andWater-Heating Boilers, of which the following is a specification, andfor which I have received Letters Patent in Great Britain, dated August14, 1894, No. 15,490.

My invention relates to steam-generators and water-heating boilers andis applicable to the several types of construction employed forstationary, locomotive, or marine purposes.

It is among the objects of my invention to provide for completelysurrounding the furnace or fire-box with water and to carry the fire ona dished plate forming the bottom of the fire-box. The bottom of theboiler-shell is to be concavo-convexed to correspond with the dishedfire-box bottom and thus provide an intermediate bottom water-space soformed that the steam and heated water may more readily escape into andthrough the waterspace around the sides and top of the fire-box. As ameans for carrying ofi ashes to the ashpit and supplying the fire withair to support combustion a large number of tubes are distributed overthe entire bottom surface of the fire-box and extended through thewaterspace between the furnace-bottom and the bottom of theboiler-shell, where they open into the ash-pit beneath. By thisconstruction fire-bars are dispensed with, the air is heated beforeentering the fire-box, and the tubes are made to act as stays for thefurnace and boiler-shell, besides serving as passages for air and ashes,and being wholly surrounded by water they cannot burn out. These tubesfor the passage of hot air and descent of ashes are preferably ferruledin their upper ends to form an internal cone that is gradually enlargeddownward for a sufficient distance to quickly and easily release theashes and prevent choking or clogging. Other objects of my inventionwill be apparent from the features of construction and novel arrangementof parts as hereinafter described.

In the annexed drawings, illustrating the invention, Figure 1 is atransverse sectional elevation of a vertical steam-boiler embodying myimprovements. Fig. 2 is ahorizontal section of the same above the bottomof the fire-box. Fig. 3 is a vertical longitudinal section of thefire-box end of a boiler of the locomotive type constructed according tomy invention. Fig. 4 is a sectional end view, and Fig. 5 a sectionalplan, of the same. Fig. 6 is a transverse sectional elevation of thefurnace end of a boiler with two flues leading from the one furnace thatis common to both said flues. Fig. '7 is a vertical longitudinal sectionof the same. Fig. 8 is a transverse vertical section of another type ofboiler to which my invention is applicable. Fig. 9 is a verticallongitudinal section of the furnace end of the same. Fig. 10 is avertical section, and Fig. 11 a half sectional plan, of another type ofsteam boiler to which my invention is adapted. Fig. 12 is an enlargedsectional detail view of portions of the bottom plates of theboiler-shell and the inclosed fire-box, showing one of the air and ashtubes with ferrule in its upper end to quickly release the ash thatenters the tube.

In each of the several figures of the drawingsthe reference-numeral 1designates the boiler-shell, and 2 the furnace or fire-box, soconstructed and arranged relatively to each other as to provide acontinuous water-space on all sides, whereby the fire-box is completelysurrounded by water. The bottom 3 of the boiler-shell and the bottom 4of the inclosed furnace or fire-box are each dished or correspondinglyconcavo-convexed and are placed a sufficient distance apart to afford awater-space 5 between them, which communicates with the water-space thatsurrounds the sides and top of the fire-box. The furnace is constructedwithout fire-bars, and the fuel is placed directly on the dished fireboxbottom. It will be seen that with this construction the concavo-convexform of the bottom water-space 5 will facilitate the escape outward andupward of steam generated by the heat transmitted through thefurnacebottom. This bottom water-space 5 is traversed by a number oftubes 6, which supply air to the furnace for supporting combustion ofthe fuel. These air-tubes 6 are either screwed or expanded into the twobottom plates 3 and 4 of the boiler-shell and fire-box, respectively,and they may be ferruled or purposes.

coned at their upper ends, so as to facilitate the discharge of ashesinto the ash-pit '7 below; but though these tubes may be conical, withtheir smaller ends next the fire to facilitate discharge of the ashes tothe ash-pit, I prefer to make them straight or with parallel sides andto ferrule the ends next to the fire, as shown in Fig. 12. The fire issupplied with fuel and stoked through the ordinary fire holes, and therefuse ashes fall through the tubes 6 into the ash pit or pan.

The combustion is "cry superior, because the tubes 6 being distributedover the entire furnace-bottom and the air having once entered the tubesit must go direct to that par ticular part of the fire to which a tubeleads, thus insuring uniform heating over the whole fire-box. Renewal ofthe tubes 6 will not be often required, as is the case with fire-bars,because being entirely surrounded by water, which is also in contactwith the plates 3 and at, both the tubes and the said plates willnot beliable to get overheated. Thus the heat that is lost in burning outfire-bars in other furnaces goes directly to heat the water surroundingthe tubes 6 in this boiler or steamgenerator. Moreover, the air tosupport combustion in passing up the tubes 6 gets heated before enteringthe furnace, and therefore cannot exercise any cooling effect on themost important part of the heating-surface. Thus the combustion of fuelin the fire-box is made so perfect and complete that nothing but fineash falls through the tubes 6, which is not worth burning over again anddoes not stop up the tubes. It will be seen, therefore, that the tubes 6serve a number of highly useful They carry refuse ashes to the ash-pit,they admit air into the fire-box for combustion and heat it before itenters the fire-box, they act as stays to the furnace and boiler-shell,and they dispense with firebars. It will be obvious also that thedishing form of the bottom plates 3 and 4 will give greaterstrength. Anumber of the tubes 6 may be tapped into these plates and the restexpanded, thereby further contributing to their efficiency as stays.

There can be nosettling of sediment on any part of the bottom hcatingsurface provided by the dished fire-box bottom 4, all thesedimentfalling onto the shell-plate 3 underneath the fire-box, where itcan do no harm. It is found also that the heat in the bottom waterspace5 is so great that the sediment is kept in constant agitation and willbe readily carried off by any suitable cock provided for that purpose.

The fire-box in vertical boilers, as in Figs. 1 and 2, may taper upwardto the crown, and from the crown tube-plate will be extended fire-tubesS, forming fines through the water and steam space of the boiler to atube-plate 9, that forms the top of the boiler-shell, and upon which maybe supported a smoke-box leading to the chimney.

Across the furnace or fire-box is preferably arranged a somewhat conicalwater-tube 10 to spread the flame and gases, increase the heatingeffect, and promote circulation of the water.

A series of horizontally-arranged air-tubes 11 may be inserted betweenthe boiler-shell and the furnace to open above the fuel and supply airfor consuming smoke with certain kinds of fuel.

Referring to Figs. 3, 4, and 5, showing a boiler of the locomotive type,the boiler-shell 1 and the inclosed firc-box 2 are cylindrical and havethe crowns of each partially domed, so as to dispense with'stayingexcept for very high pressures, and the back of the furnace is formedwith a flat tube-plate for the ends of the fire tubes or flues 8, whichare here arranged horizontally. The bottom of the firebox and thatportion of the boiler-shell beneath are dished, as before described,forming a concavo-oonvexed bottom water-space 5, through which the airand ash tubes 6 are extended. Locomotive boilers constructed upon thisprinciple possess many obvious advantages in their ability to travel agreater distance with the same quantity of fuel, a greater horse-powerfor the same size of boilershell,1ess cost in repairs,andlargely-increased durability.

The construction of boiler shown in Figs. (3 and 7 resembles theLancashire type, the furnace 2 forming an oval chamber from which twofire-flues 8 traverse the length of the boiler-shell. The furnace may hestayed by a conical water-tube 10, arranged verticall y. The bottomwater-space 5 is traversed by air-tubes 6, which in this case are shownconical to facilitate discharge of ashes into the ash-pit below.

As applied to boilers of the marine type with two or more furnaces anash chamber or chambers will be constructed in the seatin g of theboiler, into which the series of airtubes will open, and fire-bars beingdispensed with the furnaces may be of much smaller diameter than usual,as may also the shell of the boiler.

In Figs. 8 and 9, showing my invention applied to the Cornish type ofboiler, the furnace 2 is of slightly oval section to suit the fixing ofthe air-tubes 6 through the bottom water-space. A single fire-flue 8 isextended from the furnace backward through the boiler shell.

It is well known that in raising steam from cold water in horizontalboilers the boiler may be steaming at the top while the water underneath the furnace is cold, so that there is undue expansion of theplates, and this occurs every time the fire is lighted up, thus causingthe rivets and seams to be strained. This objection is obviously avoidedin my invention by reason of the water being heated simultaneously allover the fire-box, at bottom, sides, and crown, instead of at the sidesand crown only, as in ordinary boilers. Again, the heating-surface ofthe fire-box being double that IIO of ordinary boilers it is notnecessary to have the furnace so large, thus afiordin g more water andsteam space, or, if desired, the boiler-shell may be made smaller.

Figs. 10 and 11 show a form of boiler construction in which the back ofthe furnace 2 is gathered inward to provide a flat tube-plate forattachment of short horizontal tubes or fire-fines 8, opening into asmoke-box 12, attached to the boiler-shell.

In all the forms of boiler construction shown in the accompanyingdrawings and in other types of boilers to which my invention isapplicable the bottom water-space 5 is made 'concavo-convex, and thetubes 6, traversing said space, are adapted to securely stay thefire-box and boiler-shell, besides supplying heated air to every part ofthe fire and permit a free discharge of ashes to the ash pit or pan. Forwater-heating boilers as applied for various purposes the boiling of thewater is very rapid, owing to the large heating-surface of the bottombeing in immediate contact with the burning fuel and the air being sothoroughly distributed among the fuel,while in steam-boilers aconsiderable increase of evaporation will be effected from this surface,and the absence of fire-bars relieves the boiler of a very considerableWeight, besides avoiding the expense and trouble of replacing wornout ordefective bars. A very large saving of fuel, perfect circulation, andrapid generation of steam are other valuable features.

As clearly shown in Fig. 12, I prefer to make the air and ash tubes 6perfectly straight or cylindrical, and in order to prevent choking orclogging of these tubes with ashes I insert into the upper end of eachtube a ferrule 14, having an external diameter that will tightly fit thetube and an internal diameter or bore that is enlarged from abovedownward, so that ashes entering at the top are easily and quicklyreleased and allowed to fall freely into the ash pit or pan without anyliability of clogging and stopping up the tubes. The ferrules 14 can beproduced very cheaply and easily by being swaged on a taper-mandrel orturned in a lathe. By means of these ferrules 14 the ashes are releasedand have increased room to fall as soon as they enter the tubes, andconsequently there can be no choking or clogging. WVhat I claim as myinvention is 1. In steam-generators and water-heating boilers, thecombination with the boiler-shell and inclosed fire-box, each having adished bottom to form an intermediate concavo-convexed bottomwater-space, of a number of conical or tapering air-inlet tubes extendedacross said bottom water-space and opening into the fire-box andash-pit, the larger ends of said tubes, being downward to quicklydischarge the ashes into the ash-pit, substantially as described.

2. The combination with a boiler-shell, and an inclosed fire-boxcompletely surrounded by water and having a water-space between thebottoms of said boiler-shell and fire-box, of a number of tubestraversing said bottom water-space and connected with the bottoms of thefire-box and boiler-shell to supply heated air to the fire and dischargeashes to the ash-pit, and conically-bored ferrules in serted into theupper ends of said tubes with the larger ends of the ferrule-boresdownward to quickly release the ashes entering said tubes and therebyprevent choking, substantially as described.

3. The combination with a boiler-shell, and an inclosed fire-boxcompletely surrounded by water, there being a water-space between thebottoms of the said boiler-shell and firebox, of a number of tubestraversing the said bottom water-space and connecting the bottom platesof the fire-box and boiler-shell to afford passages for air and ashes,conicallybored ferrules inserted into the upper ends of said tubes withthe larger ends of the ferrule-bores downward to quickly release theashes and allow them to discharge freely, and a series of lateralair-inlet tubes above the fuel-bed, substantially as described.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

RICHARD WATSON MEWES.

"Witnesses:

GEORGE GREY, ABRAHAM BEWIOK GOLDSHOUP.

